diff options
author | Johan Hovold <johan@kernel.org> | 2020-05-13 12:09:43 +0200 |
---|---|---|
committer | Borislav Petkov <bp@suse.de> | 2020-05-27 13:05:59 +0200 |
commit | 003d80535180f74f262c40462b9fccd7f004901a (patch) | |
tree | 3e57c984acd26a5b2b4f00c094f0bfa5b139f6b9 /arch/x86/kernel/apb_timer.c | |
parent | fd52a75ca3545c965ff58a78b6ff0b0dc7d8d228 (diff) |
x86/apb_timer: Drop unused TSC calibration
Drop the APB-timer TSC calibration, which hasn't been used since the
removal of Moorestown support by commit
1a8359e411eb ("x86/mid: Remove Intel Moorestown").
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200513100944.9171-1-johan@kernel.org
Diffstat (limited to 'arch/x86/kernel/apb_timer.c')
-rw-r--r-- | arch/x86/kernel/apb_timer.c | 53 |
1 files changed, 0 insertions, 53 deletions
diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c index fe698f96617c..263eeaddb0aa 100644 --- a/arch/x86/kernel/apb_timer.c +++ b/arch/x86/kernel/apb_timer.c @@ -345,56 +345,3 @@ out_noapbt: apb_timer_block_enabled = 0; panic("failed to enable APB timer\n"); } - -/* called before apb_timer_enable, use early map */ -unsigned long apbt_quick_calibrate(void) -{ - int i, scale; - u64 old, new; - u64 t1, t2; - unsigned long khz = 0; - u32 loop, shift; - - apbt_set_mapping(); - dw_apb_clocksource_start(clocksource_apbt); - - /* check if the timer can count down, otherwise return */ - old = dw_apb_clocksource_read(clocksource_apbt); - i = 10000; - while (--i) { - if (old != dw_apb_clocksource_read(clocksource_apbt)) - break; - } - if (!i) - goto failed; - - /* count 16 ms */ - loop = (apbt_freq / 1000) << 4; - - /* restart the timer to ensure it won't get to 0 in the calibration */ - dw_apb_clocksource_start(clocksource_apbt); - - old = dw_apb_clocksource_read(clocksource_apbt); - old += loop; - - t1 = rdtsc(); - - do { - new = dw_apb_clocksource_read(clocksource_apbt); - } while (new < old); - - t2 = rdtsc(); - - shift = 5; - if (unlikely(loop >> shift == 0)) { - printk(KERN_INFO - "APBT TSC calibration failed, not enough resolution\n"); - return 0; - } - scale = (int)div_u64((t2 - t1), loop >> shift); - khz = (scale * (apbt_freq / 1000)) >> shift; - printk(KERN_INFO "TSC freq calculated by APB timer is %lu khz\n", khz); - return khz; -failed: - return 0; -} |